Commit dde01d94 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Split detaching and removing the vma 

In order to keep the assert_bind_count() valid, we need to hold the vma
page reference until after we drop the bind count. However, we must also
keep the drm_mm_remove_node() as the last action of i915_vma_unbind() so
that it serialises with the unlocked check inside i915_vma_destroy(). So
we need to split up i915_vma_remove() so that we order the detach, drop
pages and remove as required during unbind.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112067


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030192159.18404-1-chris@chris-wilson.co.uk
parent 164a4128

drivers/gpu/drm/i915/i915_vma.c

+17 −20
Original line number Diff line number Diff line
@@ -700,41 +700,35 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) 
	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));

	GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, color));



	list_add_tail(&vma->vm_link, &vma->vm->bound_list);



	if (vma->obj) {

		atomic_inc(&vma->obj->bind_count);

		assert_bind_count(vma->obj);

		struct drm_i915_gem_object *obj = vma->obj;



		atomic_inc(&obj->bind_count);

		assert_bind_count(obj);

	}

	list_add_tail(&vma->vm_link, &vma->vm->bound_list);



	return 0;

}



static void

i915_vma_remove(struct i915_vma *vma)

i915_vma_detach(struct i915_vma *vma)

{

	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));

	GEM_BUG_ON(i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND));



	list_del(&vma->vm_link);



	/*

	 * Since the unbound list is global, only move to that list if

	 * no more VMAs exist.

	 */

	if (vma->obj) {

		struct drm_i915_gem_object *obj = vma->obj;



	/*

	 * And finally now the object is completely decoupled from this

	 * vma, we can drop its hold on the backing storage and allow

	 * it to be reaped by the shrinker.

	 */

		atomic_dec(&obj->bind_count);

	list_del(&vma->vm_link);

	if (vma->obj) {

		struct drm_i915_gem_object *obj = vma->obj;



		assert_bind_count(obj);

		atomic_dec(&obj->bind_count);

	}



	drm_mm_remove_node(&vma->node);

}



static bool try_qad_pin(struct i915_vma *vma, unsigned int flags)
@@ -929,8 +923,10 @@ int i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) 
	GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));



err_remove:

	if (!i915_vma_is_bound(vma, I915_VMA_BIND_MASK))

		i915_vma_remove(vma);

	if (!i915_vma_is_bound(vma, I915_VMA_BIND_MASK)) {

		i915_vma_detach(vma);

		drm_mm_remove_node(&vma->node);

	}

err_active:

	i915_active_release(&vma->active);

err_unlock:
@@ -1187,9 +1183,10 @@ int __i915_vma_unbind(struct i915_vma *vma) 
	}

	atomic_and(~(I915_VMA_BIND_MASK | I915_VMA_ERROR), &vma->flags);



	i915_vma_detach(vma);

	vma_unbind_pages(vma);

	i915_vma_remove(vma);



	drm_mm_remove_node(&vma->node); /* pairs with i915_vma_destroy() */

	return 0;

}

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